• Proceedings of the Korea Multimedia Society Conference
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• 2000.11a
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• pp.522-524
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• 2000

일반 전자우편은 그 내용이 개방된 채로 이동하고 있어 중간에서 탈취, 변조될 가능성이 있으며, 중요한 내용들이 제 3자에게 노출되어 많은 피해자를 발생시키고 있다. 웹과 전자우편의 보안에 대한 연구는 이미 많은 부분에서 이루어져 왔으나 이러한 보안기술을 사용함에 있어 기존의 방식에서는 몇 가지 문제점이 발견되고 있다. 본 논문에서는 웹 기반 전자우편환경에, 현재까지도 뛰어난 보안성을 가진 것으로 알려져 있는 PGP 기술을 접목해서 안전하고 편리하며, 이동성이 많은 사용자 환경에 적합한 웹 기반 전자우편 보안 시스템을 구현하였고, Java 언어를 이용한 애플릿-서블릿간 통신 방식을 사용하여 기존의 방식에서 발견되는 클라이언트-서버간 통신시의 보안 취약 문제점을 해결하였다.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 1996.11a
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• pp.205-218
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• 1996

World Wide Web(WWW) has a lot of useful charaters. Easiness of use, multi-media data supporting and interactive communication capability are typical reasons why people want to use WWW. But because WWW is based on Internet, it has some security problems which originate in plain format data transmission on physical transmission line. The unique solution fer this problems is data encryption. Since theoritically proved encryption algorithms ensure data confidentiality, a unauthorized user can not know what is transmitted on network. In this paper, we propose a cryptography system which uses public key system. In detail, our public key based web security mechanism is using PGP module. PGP is a e-mail security system implemented by Phil Zimmermann. The basic idea of our propose is data encryption and integrity checking for all data which is transmitted on Web. To implement these facilities, we. use netscape browser extension technology, plug-in. Through these technology, security mechanisms are added on netscape browser.

• The Transactions of the Korea Information Processing Society
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• v.4 no.4
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• pp.1046-1058
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• 1997

WWW has taken root in Internet as a means of future shopping.But paymetn systems using tpdays show us several security vnlnerabilities.The problem that plain shpter's credit card details are transferred in Internet is included.Thnese risks can break out not only an infringement of pribate information but also economic crime.To solve these risks,we introduce the techique which implrment the encrypted WWW communication using PGP.And we propose SCCP which is new electronic payment protocol.As a result of testing with criteria from IBM,we can find that SCCP is safe and secure electronic payment protocol.As a result of testing with criteria from IBM,we can find that SCCP is safe and secure elctronic payment protocol.

• The KIPS Transactions:PartC
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• v.8C no.1
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• pp.16-22
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• 2001

There are several traditional factors of software quality. Some of them are such as correctness, reliability, efficiency, compatibility, portability, etc. In addition to them, security is required as another factor of software quality nowadays because some application programs are used as a way to attack information systems by stack frame manipulation. Each processor has its own peculiar stack frame mechanism and C language uses the characteristics of them. This paper explains the concept of security problem caused by stack frame manipulation, and the stack frame mechanism of Pentium, Alpha and SP ARC processor in detail. And then it examines the effect of stack frame mechanism on the security of programs in C language.

• Journal of Microbiology and Biotechnology
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• v.25 no.10
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• pp.1621-1628
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• 2015

Chlamydia possesses a conserved 7.5 kb plasmid that is known to play an important role in chlamydial pathogenesis, since some chlamydial organisms lacking the plasmid are attenuated. The chlamydial transformation system developed recently required the use of plasmid-free organisms. Thus, the generation and identification of plasmid-free organisms represent a key step in understanding chlamydial pathogenic mechanisms. A tricolor immunofluorescence assay for simultaneously detecting the plasmid-encoded Pgp3 and whole organisms plus DNA staining was used to screen C. muridarum organisms selected with novobiocin. PCR was used to detect the plasmid genes. Next-generation sequencing was then used to sequence the genomes of plasmid-free C. muridarum candidates and the parental C. muridarum Nigg strain. We generated five independent clones of plasmid-free C. muridarum organisms by using a combination of novobiocin treatment and screening plaque-purified clones with anti-Pgp3 antibody. The clones were confirmed to lack plasmid genes by PCR analysis. No GlgA protein or glycogen accumulation was detected in cells infected with the plasmid-free clones. More importantly, whole-genome sequencing characterization of the plasmid-free C. muridarum organism and the parental C. muridarum Nigg strain revealed no additional mutations other than loss of the plasmid in the plasmid-free C. muridarum organism. Thus, the Pgp3-based immunofluorescence assay has allowed us to identify authentic plasmid-free organisms that are useful for further investigating chlamydial pathogenic mechanisms.

• Journal of Microbiology and Biotechnology
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• v.22 no.11
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• pp.1549-1556
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• 2012

Endophytic fungi were isolated from roots of six halophytes in Suncheon Bay. The endophytic fungi of 35 species isolated from halophytes were identified by internal transcribed spacer (ITS) containing the ITS1, 5.8s, and ITS2 regions. All fungal strains were analyzed to diversity at the genus level. Fungal culture filtrates (FCF) of endophytic fungi were treated to Waito-c rice (WR) seedling for plant growth-promoting verification. It was confirmed that fungal strain Sj-2-2 provided plant growth promotion (PGP) to WR seedling. Then, PGP of Suaeda japonica was confirmed by treating culture filtrate of Sj-2-2. As a result, it was verified that culture filtrate of Sj-2-2 had more advanced PGP than positive control when treated to S. japonica. The secondary metabolites involved in culture filtrate of Sj-2-2 were identified by HPLC and GC-MS SIM analysis. The presence of physiologically bioactive gibberellins (GAs) and other inactive GAs in culture filtrate of Sj-2-2 was detected. The molecular analysis of sequences of Sj-2-2 showed the similarity to Penicillium sp. of 99% homology. The PGP of Sj-2-2 as well as symbiosis between endophytic fungi and halophytes growing naturally in salt marsh was confirmed. Sj-2-2 was identified as a new fungal strain producing GAs by molecular analysis of sequences. Consequently, the Sj-2-2 fungal strain was named as Penicillium sp. Sj-2-2. In this study, the diversity of endophytic fungi isolated from roots of halophytes in salt marsh and the PGP of a new gibberellin-producing fungal strain were confirmed.

• Natural Product Sciences
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• v.18 no.4
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• pp.239-243
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• 2012

Mushrooms have a long history of use in traditional medicine, and hundreds of novel constituents in mushrooms with miraculous biological properties have been identified recently. Although diverse effects for medicinal use of mushrooms such as anticancer activity are proven, their reversal activities of drug resistance in cancer cells was rarely reported so far. In the search for novel medicinal use of mushrooms, we tested the multidrug resistance (MDR) reversal activities of diverse mushrooms collected from Korea. Among, the mushroom extracts tested, Cantharellus cibarius (M02) and Russula emetica (M12) revealed MDR reversal activities of paclitaxel in the P-glycoprotein (Pgp)-positive HCT15 and MES-SA/dX5 cancer cells, but not in the Pgp-negative A549 and MES-SA cancer cells. In addition, these mushrooms also enhanced the cytotoxicity of doxorubicin, another well-kwown Pgp-associated anticancer drug against MES-SA/DX5 cells, but not against MES-SA cells. Meanwhile, the cytotoxicity of cisplatin, a well-known Pgp-non-associated anticancer drug, was not affected by the mushrooms all the cells tested. From these results, we suspected that some ingredients of M02 and M12 have Pgp-associated MDR reversal activities.

• The Korean Journal of Nuclear Medicine
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• v.38 no.2
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• pp.180-189
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• 2004

Although the outcome of cancer patients after cytotoxic chemotherapy is related diverse mechanisms, multidrug resistance (MDR) for chemotherapeutic drugs due to cellular P-glycoprotein (Pgp) or multidrug-resistance associated protein (MRP) is most important factor in the chemotherapy failure to cancer. A large number of pharmacologic compounds, including verapamil, quinidine, tamoxifen, cyclosporin A and quinolone derivatives have been reported to overcome MDR. Single photon emission computed tomography (SPECT) and positron emission tomography (PET) are available for the detection of Pgp and MRP-mediated transporter. $^{99m}Tc$-MIBI and other $^{99m}Tc$-radiopharmaceuticals are substrates for Pgp and MRP, and have been used in clinical studies for tumor imaging, and to visualize blockade of PgP-mediated transport after modulation of Pgp pump. Colchicine, verapamil and daunorubicin labeled with $^{11}C$ have been evaluated for the quantification of Pgp-mediated transport with PET in vivo and reported to be feasible substrates with which to image Pgp function in tumors. Leukotrienes are specific substrates for MRP and $N-[^{11}C]acetyl-leukotriene$ E4 provides an opportunity to study MRP function non-invasively in vivo. SPECT and PET pharmaceuticals have successfully used to evaluate pharmacologic effects of MDR modulators. Imaging of MDR and reversal of MDR with bioluminescence in a living animal is also evaluated for future clinical trial. We have described recent advances in molecular imaging of MDR and reviewed recent publications regarding feasibility of SPECT and PET imaging to study the functionality of MDR transporters in vivo.

• Proceedings of the Korea Information Processing Society Conference
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• 2002.11c
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• pp.2379-2382
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• 2002

요즘 전자우편(E-mail) 서비스를 사용하게 되면서, 스팸 메일이라고 불리 우는 광고성 메일이 무분별하게 전자우편에 침입하고 있다. 요즘과 같이 정보의 중요성과 개인의 사생활이 강조되는 시점에서 다른 사람이 중간에 메일을 가로채어 읽거나 해킹 하여 전혀 다른 내용으로 바꾸어 배포하거나 바뀐 내용을 전송하거나 과도한 스팸메일 때문에 자신의 메일 계정에 부하가 걸려서 중용한 메일을 못 받게 된다면 보통 심각한 일이 아닐 수 없다. 본 논문에서는 이것을 해결하기 위하여, PGP(Pretty Good Privacy)라는 기술과 문자열 처리를 이용하여 전자우편의 보안성 향상과 문자열 처리를 통해 스팸메일을 줄이는 방법을 제안한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.05b
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• pp.1043-1046
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• 2003

정보화 사회가 도래하고 우편이나 통신체계도 물리적인 공간에서 인터넷(Internet)이라는 가상 공간으로 점차 옮겨져 광범위하게 사용되고 있다. 전자우편의 중요성이 대두되면서 스팸 메일 (Spam-Mail)로 인한 여러 가지 피해들이 속출하고 있다 특히, 많은 사람들이 성인광고 스팸메일로 인해 상당히 곤혹스러운 경우를 경험을 하고 있다. 본 논문에서는 PGP(Pretty Good Privacy)의 개념을 이용해서 사용자 인증(User Authentication) 기능을 수행하고, 인증되지 않는 사용자가 보낸 메일에 대해서는 텍스트 분석뿐만이 아니라 이미지와 동영상을 처리해서 성인광고 메일 여부를 판단하는 메일 시스템을 제안한다. 우리의 조사에 의하면, 성인광고메일을 차단하는 메일시스템에 관한 연구는 거의 발표되지 않고 있다.